Ice tray and slip surface flexible grid



1948- H. Y. JENNINGS ICE TRAY AND SLIP SURFACE FLEXIBLE GRID Filed Nov. 5, 1942 ?atente Dec. 7, 395

Harley Y. Jennings, Clio, Mich., assignor to Copeman" Laboratories Company, Flint, Mich, a cor-- poration of Michigan Application November 5, 1942, Serial No. 464,640

7 Claims. (Cl. 62-1085) This application is a continuation in part of my copending application Serial No. 334,293, filed May 9, 1940, which was a continuation in part of my prior application Serial No. 254,578, filed February 4, 1939. The first named of said applications matured into Patent No. 2,303,938 on December 1, 1942, and the second named application has become abandoned.

This lnventionrelates to ice tray and slip surface flexible grid for mechanical, refrigerators and to grids therefor, and particularly to containers and grids of the flexible non-metallic type disclosed in Copeman Reissue Patents 17,278 and 17,279 and Copeman Patent No. 1,817,544.

Millions of devices made under these patents have been in use for many years and have given completely satisfactory service. Improvements have been made from time to time, as disclosed in the patented art, but such improvements have been along the line of the shape and contours of the devices, and little attention has been paid to the physical characteristics of the I rubber surfaces.

One of the most satisfactory embodiments of the invention in use today is the combination of a metal tray with a flexible rubber grid. The particular type of tray best suited to this combination is the so-called Presto tray, disclosedin Geyer Patent No. 2,122,937, in whichthe metal tray is constructed to permit a limited distortion thereof for separating the frozen ice blocks from the metal surfaces of the tray. The best results with a tray of this type are obtained by treating the ice-contacting surfaces of the tray with a non-metallic coating as disclosed in Hathorne Patent No. 1,932,731. Such a construction is particularly advantageous when the tray with its frozen contents is first flexed, as disclosed in the aforesaid Geyer Patent No. 2,122,- 937, to release the frozen mass of ice with the flexible rubber grid embedded therein, after which the individual cubes or blocks of ice are separated from the grid as needed.

faces. Thus, in two simple operations, the user has immediately available a tray full ofrindividual separate ice blocks which may be dumped into a storage compartment so that the tray and grid may again be used for the freezing function, whereas in the Geyer construction each cube must be individually picked from the rubber grid, and if all the cubes are not needed immediately -the usual practice is to leave the grid,

with such cubes as have not been used, in the metal tray until they are needed. Thus, in the Geyer construction, the tray and grid are not immediately available for the freezing of additional cubes or blocks until the entire contents of the tray from the previous freezing have been used.

Obviously, in order that the Gaugler construction be, successful, it is necessary that the adhesion of the ice blocks to the rubber grid be less than the adhesion of the same blocks to the metal tray, as otherwise the blocks would be separated from the tray when an attempt was made to strip the grid from the ice. This situation is helped somewhat if the metal tray is not coated with a water-repellent surface, or

' between rubber and ice when the ice is frozen I have found by repeated experiments that the I in contact with a rubber surface, and the main reason rubber trays and grids are successful is that the inherent flexibility and resiliency of the rubber permits the rubber to be peeled from the ice andto resume its original shape after the ice has been separated from it.

In other words, ordinary .soft rubber has a relatively rough or non-slip surface and the result is that the friction between the rubber and the ice, when an attempt is made to strip a rubber grid from a frozen mass as disclosed by Gaugler, is sometimes greater than the adhesion between the ice blocks and the metal tray, with the result that often some of the cubes cling to the grid as it is stripped, and thus defeat the object of the invention.

Moreover, even if the grid can be stripped from the ice mass without pulling some of the ice blocks from the tray, the force required to be exerted by the user is greater than should be required to make the device a practical article for everyday use.

I have found, however, that if the rubber used in making the grids is treated as by mixing certain ingredients, such as waxes or resins, with the usual rubber mix, which ingredients "bloom" or otherwise come to the surface after the grid is molded. or if (certain surface treatments are given to the grid after it is made), I am able'to obtain a rubber grid, the surfaces of which are 'easily slippable, or relatively frictionless with respect to the ice formed around the grid and contacting the surfaces thereof and which are also of my invention and is a material factor in permitting the withdrawal of the grid without any material reduction in its cross-section.

When a rubber grid made according to the present invention is removed from the ice in the tray, leaving the ice cubes formed by the grid adhering to the metal tray surfaces, the grid, because of its relatively water-repellent and frictionless surface, really slips rather than peels from the ice as described in the aforesaid Gauglcr patent. By this I mean that the reduction in the cross-section of the grid partition'as the grid is being slipped from between the ice cubes is relatively small as compared with the reduction in cross section necessary for operation of the Gaugler construction, and the main reason for the easy removal of a grid constructed in accordance with my invention is the. water-repellent and frictionless surface aforesaid.

The fact that the grid is made of a soft re- -silient material, such as rubber, enables it to take up the expansion produced by the changing of water to ice. This action compresses the rubber and of course causes some reduction in its cross-section during the freezing process. This is really an advantage as compared with a metal grid, because in the latter device the expanded ice binds the rigid walls of the grid firmly. However, even though the rubber grid made according to my invention may be compressed as the ice freezes, there is no material stretching of the grid sections as it is removed from the ice for the reasons previously explained; that is, its low adhesion to the ice and its relatively frictionless surfaces.

Another improvement of the Gaugler structure vision of a rigid central bar in the grid to facilitate the removal thereof. When the bar is rigid one end may be pivoted on the edge of the tray to provide leverage.

Other objects and features of the invention having to do with detail of construction and with treatment of the grids will be further brought out in the following description and claims.

In the drawings:

Fig. 1 is a perspective view of an ice tray containing a rubber grid.

Fig. 2 is a sectional view on lines 2-2 of Fig. 1 showing, in dotted lines, the grid being removed from the tray and its frozen contents by elevating one end thereof.

Fig. 31s a section taken on line 8-! of Fig. 1.

Fig. 4 is a bottom plan view of a portion of a grid'illustrating the tapered walls thereof.

Fig. 6 1s an enlarged partial view of the pivot end 'of the removing bar of the grid.

Fig. 6 is a partial perspective view of a conventional rubber tray having surfaces produced according to my invention.

Referring to the drawings, l0 denotes a metal tray capable of limited distortion as disclosed in the aforesaid Geyer Patent No. 2,122,937. Although this type of tray is preferred I have found that any metal tray which can be twisted slightly will answer the purposes of my invention. Also preferably the interior surfaces of the tray should be untreated; or should be treated only slightly so that the ice cubes will always 5 adhere to the walls of the tray when the grid is removed or ."slipped" from the ice.

The grid ii is preferably made of soft flexible rubber of high quality and comprises the usual longitudinal center strip l2 and a plurality of cross-pieces l3. It is desirable that the grid should extend a slight distance above the side walls of the tray so that the upper part of the grid shall not be enclosed by a layer of ice when the contents of the tray are frozen. Preferably or in other words, be of gradually decreasing thickness from top to bottom to assist in the removal of the grid, and it is also desirable that the cross pieces I3 should taper or be of gradually decreasing thickness from the center strip toward the side walls of the tray. The general contour of the grid members is'dlsclosed in detail in F18. 4.

A relatively heavy reinforcing bead I4 is molded along the top of the center strip i2 and is preferably rigid; a reinforcing metal insert i5 may be molded into the bead to assist in stripping the grid from the tray. Further, it is possible and desirable to mold similar reinforcing beads IS on the top of each of the cross pieces i8. A handle or finger grip I1 is molded integrally with the grid at one end of the center piece to afford a means for grasping the grid when it is being stripped from the tray and its frozen contents.

The other end of the center reinforcement is shown in detail in Figs. 2 and 5. This end is provided. with a fin-like depending portion i8 which forms a notch to receive the edge 20 of the end wall of tray ID. The end of the tray then serves as a fulcrum for the center bar It and greatly facilitates the removal of the grid. As shown by the dotted lines of Fig. 2, the grids it are pulled aside from, as well as up from, their recesses so that the removal is easy.

In accordance with this invention, the manner of producing a desirable finish on rubber for easy ice removal is to incorporate with the usual rubber mix a suitable amount of wax or resin or mixtures of wax and resin. I have used Heliozone, material prepared and sold by E. I. DuPont de Nemours & Company of Wilmington, Delaware, which comprises a mixture of amorphous and micro-crystalline waxes derived from petroleum base hydrocarbons having a melting point of 73-7'7 C., when determined by the method designated D127-30 described by the American Society of Testing Materials. I have also used a synthetic resin called Nevellite No. 3 made by the Neville Company ,nf Pittsburgh, Pennsylvania,

75 use they tend to drive toward the surface of a the center l2 and the cross pieces l3 should taper,

acoasoe tray or grid in which they are incorporated, to form a smooth water-repellent film. This particular property of surface migration is commonly referred to as "blooming.

Any suitable rubber mix may be used depending on the physical properties, such as, resiliency and transparency, which are desired. Further, I

have found that the invention comprehends the treatment not only of natural rubber and its compounds but such rubber substance or substances having rubber-like properties, as neoprene or 'Ihiokol, which is a substance known as polysulfide resulting from the condensation reaction of a dihalide with sodium tetrasulfide; and

wherever in the specification and following claims the term rubber is used, it is intended to include not only rubber, natural or synthetic, but such rubber substitutes as are capable of reacting with the substances herein described or their equivalents, to produce similar results.

. Fillers, such as zinc oxide and magnesium carbonate or zinc carbonate may be used and the proportion of the wax or resin "blooming material may vary from 2 to 10 parts, depending on the physical properties of the material used. In

any event, the finished product is a rubber tray or grid having a surface film of wax resin for contacting the substance to be frozen, which film is constantly being replaced by surface migration.

It would be noted that the formation of rubber 3 trays and grids from the wax-rubber mixture is a physical mixture without any chemical action. However, a surface condition is produced which is different from that of ordinary rubber and in the append-ed claims I use the term "treated surfaces" and similar expressions to include those which are produced as a result of a hysical mixture of se- 'lected substances.

While I have shown and described specific embodiments of the invention. it is readily apparent 40 that other forms might be adapted, coming within the scope of the following claims.

In the claims:

1. .As a new article of manufacture, a sharp freezing container for substances to be frozen, and

partitions for dividing the container into a pillrality of ice cube molds, said partitions being formed of resilient easily distortable rubber which has incorporated therein a substance of such a nature that it will migrate to the surfaces of said so partitions to form water-repellent, slippable surfaces for contact with the frozen substance in said container.

2. As a new article of manufacture, a sharp freezing container for substances to be frozen, and

partitions for dividing the container into a plurality of ice cube molds, said partitions being formed of resilient easily distortable rubber which has incorporated therein a wax of such a nature that it will migrate to the surfaces of said parti- 00 Number tions to form water-repellent, slippable surfaces for contact with the frozen substance in said conltainer.

3. As a new article of manufacture, a sharp freezing container for substances tobe fmzen, and P itio s for dividing the container into a pinrallty of ice cube molds, said partitions being formed of resilient easily distortable rubber which has incorporated therein a resin of such a nature that it will migrate to the surfaces of said partitions to form water-repellent, slippable surfaces for contact with the frozen substance in said container.

4. As a new article of manufacture, a sharp freezing container for substances to be frozen, and means forming partitions for dividing the container into a plurality of ice cube molds comprising an easily distortable material such as rubber and means incorporated within such material adapted to migrate to the surface thereof to form self-replacing water-repellent, slippable surfaces.

5. As a new article of manufacture, a sharp freezing container for substances to be frozen, and means forming partitions for dividing the container into a plurality of ice cube molds comprising an easily distortable rubber and means associated therewith to form a water-repellent slippable surface thereon and incorporated in such rubber in a manner to replace continuously such surface when removed by wear and mechanical abrasion.

6. As a new article of manufacture, a sharp freezing container for substances to be frozen. and means forming partitions for dividing the container into a plurality of ice cube molds comprising a mixture adapted to form easily distortable walls similar in physical characteristics to that of rubber, one of the ingredients of which is so related to the others as to have surface migration tendencies, such ingredient being of a nature to form a water-repellent slippable surface.

'7. For use in a sharp freezing container for holding water to befrozen and of a type adapted to be positioned in heat-conducting relation with the low-side of a refrigerating system and comprising a distortable, normally smooth tray, 9. removable unitary grid structure being characterized by the fact that it is formed of an homogebond therebetwee'n.

HARLEY Y. JENNINGS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 2,004,519 Chilton June 11, 1935 2,035,543 Gaugler Mar. 31, 1936 2,135,022 Anderson Nov. 1, 1938 2,155,592 Hardy Apr. 25, 1939 2,191,263 Waring Feb. 20, 1940 2,803,938 Jennings Dec. 1, 1942 

